Flat path extractor



June 11, 1968 E. H. ROFE FLAT PATH EXTRACTOR 2 Sheets-Sheet 1 Filed Oct.11, 1965 FIG.

FIGS

E m mR m V D mm W D E ATTORNEYS June 11, 1968 E. H ROFE 3,387,717

FLAT PATH EXTRACTOR Filed Oct. 11, 1965 2 Sheets-Sheet /-57' .41.TERA/472.

Air/s 2N0. 4L7? AXIS FIG.4

INVENTOR EDWARD H. ROFE ATTORNEYS United States Patent 3,387,717 FLATPATH EXTRACTOR Edward H. Rofe, 2781 Acorn Road, Bloomfield Hills, Mich.48013 Filed Get. 11, 1965, Set. No. 494,740 3 Claims. (Cl. 214-1) Thisinvention relates generally to work-handling devices and moreparticularly to devices for withdrawing stampings from presses.

In removing sheet metal stampings from power presses, it is necessary tolift the stamping slightly before it can be horizontally withdrawn fromthe press. This initial lifting is necessary to permit the stamping toclear the forming contours of the die. Since a variety of dieconfigurations may be utilized in a given press, it is desirable thatassociated equipment for mechanically withdrawing a stamping from thepress have a variable stroke pattern so that the necessary lift will beavailable for any depth of draw.

Accordingly, it is an object of this invention to provide a mechanicalwork-handling device for removing stampings from power presses whereinthe motion of the workhandling arm is initially vertical followed by asubstantially horizontal path with respect to the die.

It is a further object of this invention to provide a workhandling armwherein the shape of the stroke described by the Work-handling arm maybe selectively varied.

Other objects, advantages and novel features of this invention willbecome apparent from the following specification when considered inconjunction with the accompanying drawings.

In these drawings:

FIG. 1 is a side view of the Work-handling device of this invention,with one side of the frame removed to expose the inner mechanism;

FIG. 2 is a partially fragmented front view of the device illustrated inFIG. 1;

FIG. 3 is a fragmentary view of a portion of the linkage, illustratingthe lift adjusting screw;

FIG. 4 is a simplified diagram of the mechanism of this inventionshowing the variety of work-handling arm strokes which may be obtained.

Referring to the drawings, the motion of the work-gripping assembly iscontrolled through a linkage by means of a pneumatic actuating cylinder12. Cylinder 12 is pivotally mounted on pin 13- to a pair of members 14.Similarly, a pair of links 16 are pivotally mounted by pins 18 to framemembers 14. The motion of the pneumatic cylinder 12 is transmitted tolinks 16 by means of a clevis and pin connection 26, 22.

Swing plates 24 are pivotally mounted on links 16 by pins 26. Followers28 located at the upper end of each swing plate 24 each ride in a guideslot formed between two gibs 30 which are secured to each frame member14. These followers are rotatably mounted on follower shaft 32,supported between the two swing plates. Provision is made for mountinggibs 30 in other parallel but nonvertical (as viewed in FIG. 1)orientations. This could be achieved by means of additional mountingholes or by slots. The function of such other positions will beexplained below.

A hydraulic snubber 34 is secured by a bracket 36 to frame 14- at itslower end and at its upper end is rigidly secured to swing plates 24 bymeans of a bracket 38. The connection between snubber 34 and bracket 33is through a pin 40, so that rotational motion therebetween may beachieved. Snubber 34 is designed to provide cushioning or resistanceonly on the inward (downward) stroke of its piston, and to providesubstantially no resistance to the outer (upward) stroke.

3,387,717 Patented June 11, 1968 ice The lower arm 42 of the deviceforms an extension of swing plates 24 and may be telescoped with respectthereto through clamp 44. Further adjustment of the position of gripperassembly 10' relative to swing plates 24 is provided by pivot pin 46.Lower arm 42 may pivot about this pin, and bolt 48 may be insertedthrough any one of a plurality of holes 49 in the lower portion of swingplates 24.

A lift adjustment screw 50 is threaded through a portion 52 of the frameand abuts a boss on link 16 (see FIG. 3). For a given setting of theposition of gripper assembly 10 relative to swing plates 24, screw 50controls the limit of travel of the gripper assembly into the press(that is, to the right as viewed in FIG. 1). Similar control of thetravel of the gripper could alternatively be achieved by an adjustablestop (not illustrated) at the lower end of the guide slot between gibs30. Other effects of variations in the lift adjustment screw will bediscussed hereinafter.

FIG. 4 illustrates the variation in the path of the gripper from thepick-up point 54 which may be obtained by adjustments in the setting oflift screw 50. With the screw in a relatively Withdrawn position, sothat follower 28 is initially at position A in FIG. 4, the path ofpick-up point 54 is as illustrated at A at the bottom of the figure.

It can be seen that path A is characterized by a substantially verticaldisplacement at the beginning of the stroke, following which the strokebecomes flat and substantially horizontal. With successively higherpositions of screw 50, producing initial points B and C of follower 28,the lift of pick-up point 54 becomes less at its origin, as indicated bypaths B and C respectively. It is to be understood that the relativeproportions of the mechanism as illustrated in FIG. 4 would notnecessarily produce the extraction paths indicated. The illustratedextraction paths, rather than the mechanism dimensions, are intended tobe illustrative of the desired characteristics of the device.

The shape of the extraction path can also be modified by adjustments ingibs 36 As discussed above, provision is made for mounting gibs 30 toframe members 14 in other parallel, non-vertical orientations. If theyare inclined so as to produce the first guide slot axis (as illustratedand denoted in FIG. 4), the initial lift from the pick-up point will beincreased, the length of the extrac tion stroke will be reduced, and thepath will be inclined upwardly and to the left toward the end of thestroke. If the guide slot is inclined as in the second position of FIG.4, the initial lift from the pick-up point will be increased, the lengthof the extraction stroke will be reduced, and the path will besubstantially horizontal, with very little upward are near itstermination.

In any of these settings, the extraction path retains its essentiallyfiat path toward the end of the stroke. This is because as link 16rotates counterclockwise about point 18 (see FIG. 4), point 26 will fallon a line connecting points 18 and 28. At that pisition, point 28 willreach its uppermost point, point X in FIG. 4. Further rotation of link16 will cause point 28 to return slightly to point Y, which prevents thegripper assembly 10 from assuming an upward are near the end of thestroke.

OPERATION The mechanism is first set so that the gripper jaws will reachand grip the piece to be extracted from the press. This is accomplishedby appropriate setting of bolt 48, clamp 44, and adjustments (notillustrated) on gripper assembly 10. The desired lift and extractionpath is then established by appropriate setting of lift screw 50 andgibs 30.

Upon an electrical signal from the press indicating that the part isready for extraction, a valve on gripper as- 3 sembly 10 extends thegripper and closes the jaws on the part. Cylinder 12 is then actuated,initiating the extraction stroke.

As discussed above, snubber 34 provides resistance only on the downwardstroke. This means that no power is consumed by the snubber during theinitial and intermediate portion of the extraction stroke, since thesnubber piston is travelling upward as follower 28 moves to point X. Atthe terminal portion of the extraction stroke, and during the finalportion of the return stroke, cushioning of the linkage is provided,since the snubber piston is then travelling downward. Maximum snubbin isprovided at the end of the return stroke, since point 26 and point 28are then moving at maximum velocity along a purely vertical path.

This invention may be further developed within the scope of thefollowing claims. It is to be understood that the above description isillustrative of only a single embodiment and is not to be read in astrictly limited sense.

I now claim:

1. A work-handling device comprising a frame; a first link pivoted onsaid frame for rocking movements in a vertical plane about a first axis;actuating means connected to said first link for rocking the latterabout said axis; vertically extending guide means on said frame; asecond link; means pivoting said second link to said first link forvertical movement and for simultaneous rocking movements with said firstlink but in an opposite direction in response to rocking of said firstlink by said actuating means; follower means on said second link nearthe upper end thereof, above said means pivoting said second link tosaid first link, in guiding relation with said guide means for guidingsaid second link vertically, said follower means forming a second axisabout which said second link may rock in a vertical plane; andwork-gripping means carried by said second link for movements with thelatter, the pivotal connections of said links to one another and thepivotal connection of said actuating means to said first link being suchthat said simultaneous rocking of said links efiects movement of saidwork-gripping means along a path having an initial substantiallyvertical component and a secondary substantially horizontal component.

2. The combination defined in claim 1 in which said guide meanscomprises a slot and stop means is mounted in said slot for varying themovement of the fol-lower means.

3. The device set forth in claim 1 including fluid means acting on saidsecond link for cushioning said work-gripping means at the ends of saidpath.

References Cited UNITED STATES PATENTS 3,209,922 10/1965 Melvin 214-12,609,776 9/1952 Sahlin 72-426 3,040,685 6/1962 Ridley 7224 GERALD M.FORLENZA, Primary Examiner.

G. F. ABRAHAM, Assistant Examiner.

1. A WORK-HANDLING DEVICE COMPRISING A FRAME; A FIRST LINK PIVOTED ONSAID FRAME FOR ROCKING MOVEMENTS IN A VERTICAL PLANE ABOUT A FIRST AXIS;ACTUATING MEANS CONNECTED TO SAID FIRST LINK FOR ROCKING THE LATTERABOUT SAID AXIS; VERTICALLY EXTENDING GUIDE MEANS ON SAID FRAME; ASECOND LINK; MEANS PIVOTING SAID SECOND LINK TO SAID FIRST LINK FORVERTICAL MOVEMENT AND FOR SIMULTANEOUS ROCKING MOVEMENTS WITH SAID FIRSTLINK BUT IN AN OPPOSITE DIRECTION IN RESPONSE TO ROCKING OF SAID FIRSTLINK BY SAID ACTUATING MEANS; FOLLOWER MEANS ON SAID SECOND LINK NEARTHE UPPER END THEREOF, ABOVE SAID MEANS PIVOTING SAID SECOND LINK TOSAID FIRST LINK, IN GUIDING RELATION WITH SAID GUIDE MEANS FOR GUIDINGSAID SECOND LINK VERTICALLY, SAID FOLLOWER MEANS FORMING A SECOND AXISABOUT WHICH SAID SECOND LINK